Iodine detergent solution



United States Patent 3,274,116 IODINE DETERGENT SOLUTION Jack F. Mills, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware N0 Drawing. Filed Aug. 5, 1963, Ser. No. 300,063 5 Claims. '(Cl. 252-406) This application is a continuation-in-part of my copending application, Serial No. 51,547, filed on August 24, 1960, now abandoned.

This invention relates to an iodine-containing detergent solution. More particularly, it relates to a combination of iodine with an organic anionic detergent and an alkylene glycol derivative for use as a germicidal cleansing solution.

Because of its germicidal properties, iodine is a desirable and commonly used ingredient in sanitizing rinses and cleansing solutions for industrial and home use. The solubility of iodine in water is low and this dasadvantage has been overcome in the past by using a substance which will form a water-soluble complex with the iodine. Such substances may be an inorganic salt such as potassium iodide or an organic compound such as a nonionic surfactant or relatively high molecular weight. The soluble complexes so formed tend to lessen the effective strength of the iodine solution, for at least some part of the iodine is held in these combinations in a less germicidal or inactive form.

I have found that iodine is solubilized in a water solution by a combination of a highly water-soluble organic anionic detergent with a lower alkyl monoether of ethylene glycol. The solubilizing effect is a property of this combination and is not exhibited by either of the components alone except on a very limited scale. I have found further that iodine thus solubilized remains entirely available in the active form and the whole forms a highly stable homogeneous solution capable of extended storage. Such solutions may conveniently be made up as stable concentrates containing about 15% by weight of free iodine and thes concentrates are then suitably diluted for use when needed.

Anionic detergents found suitable for this purpose are salts of sulfated or sulfonated organic compounds which are highly soluble in water, that is, to the extent of about 25 ,g./ 100 g. solution or better, and are preferably effective in aqueous acid solution. Examples of these are suitably soluble salts of alkylarylsulfonic acids, alkylated arylether sulfonic acids, and sulfated alkyl compounds such as ammonium or alkali metal salts of sulfonated higher alkylbenzenes, higher alkyldiphenyl ether sulfomates, and higher primary alkyl sulfates. Particularly useful because of their high solubility in water and in aqueous solutions of electrolytes are salts of alkyldiphenyl ether sulfonates such as disodium dodecyldiphenyl ether disulfonates.

The lower alkyl monoethers of ethylene glycol suitable for use in this composition are the methyl, ethyl, propyl, and butyl monoethers. The monomethyl ether, Z-methoxyethanol, is preferred.

The iodine may be present as free elemental iodine or as combined iodine, in a water-soluble inorganic iodidebromate or iodide-iodate salt combination which releases free iodine when acidified in water solution. Preferably, such a salt combination is made up of sodium or potassium iodide and bromate in approximately the theoretical proportion of six moles of iodide to one mole of bromate. A small excess of bromate or iodate will regenerate reduced iodine as it forms in the solution after acidification and dilution and such excess bromate or iodate thereby serves to prolong the effective life of the solution. About 15% of excess bromate or iodate based on the available iodine is preferred.

If such a salt combination is used as a source of iodine, the acid may be added to the concentrate just before it is diluted for use. Such a neutral concentrate may be stored indefinitely without loss of iodine.

An acid of suitable strength and compatible with the other components is used to release free iodine from the above-mentioned salt combinations. Acid in excess of the amount necessary for this purpose is preferably used and such an acid preferably is also used in a solution made up with elemental iodine in order to obtain good stability. Suitable acids are phosphoric acid, hydrochloric acid, sulfamic acid, oxalic acid, and sodium bisulfate. Mixtures of such acids may be employed.

The quantity of acid required to maintain a stable solution and prevent excessive loss of iodine is that amount necessary to provide a solution having a pH less than 6.0 when diluted for use. A pH of about 2-5 is preferred. About l-lO parts of one or more acids such as named per part by Weight of iodine provides a suitably acidic solution.

The proportions of the detergent and glycol ether components may be varied somewhat in the germicidal formulation. About 5 to about 15 parts by weight of detergent and about 5 to about 15 parts of glycol ether per part of iodine gives stable, homogeneous solutions. For most effective solubilization of the iodine, the detergent and the glycol ether are employed in approximately equal Weights.

It is ordinarily most convenient to make up these formulations as concentrated aqueous solutions containing about 1-5% by weight of iodine and the other components in amounts as described above. Preferably, such concentrates contain 5-15 by weight of a suitable acid or acid mixture. Phosphoric acid or mixtures of phosphoric and hydrochloric acids are ordinarily used. Formulations embodying my invention may be made up with widely varying compositions in the above approximate ranges to suit different applications. These concentr-ated formulations can then be diluted as required for a particular use.

Some illustrative formulations are shown in the following examples:

Benax 2A1 surfactant, a product of The Dow Chemical Company, is disodium dodecyldiphenyl ether disulfonate.

The potassium iodide and sodium bromate were dissolved in the Benax 2A1 solution. The 2-methoxyethanol and phosphoric acid were stirred in and the Whole was diluted with water to make a total of g. of a clear homogeneous solution containing the theoretical quantity of available iodine. This solution was exceptionally stable and showed little loss of iodine on long standing. No decrease in available iodine content was found after one weeks standing at room temperature. Better than 90% of the original iodine was present in available form after the solution had stood for one year.

Example 2 Using the same materials, a more concentrated formulation was prepared.

50% aqueous Benax 2A1 64.6 Potassium iodide 4.7 Sodium bromate 0.7 Z-methoxyethanol 20.0 85% phosphoric acid -a 10.0

Total 100.0

The components were mixed as in Example 1 to give a clear and stable, although somewhat more viscous solu- Iodimetric titration showed the presence in the solution of 1.74% by weight of available iodine, 99% of that theoretically possible.

Example 4 A solution was made up from the same quantities of materials shown in Example 3 except that the glycol ether was 2-butoxyethanol. This solution was homogeneous and stable on standing. The theoretical quantity of iodine was present in available form.

Homogeneous solutions of good stability are obtained when the iodide-bromate salt combination used in these examples is replaced by an equivalent quantity of elemental iodine. The retention of available iodine in such solutions is improved when a small amount of bromate or iodate is also present in the solution. About 15% by weight of sodium bromate based on the iodine present is a suitable quantity.

Any of various sulfated or sulfonated organic surface active agents may be used as the anionic detergent component of these iodine solutions with approximately equal effectiveness. Examples 5 and 6 illustrate such compositions.

Example 5 The following ingredients were mixed to obtain a clear solution:

U1trawet K is a trademark for a commercially available sorhum alkylbenzcne sulfonate.

The solution was stable on standing and it contained. the theoretical quantity of titratable free iodine.

4 Example 6 A solution was made up as in Example 5 wherein the Ultrawet K was replaced by an equal quantity of Duponol MER This solution was also clear and stable. It contained the theoretical amount of free iodine.

The solutions of Examples 1, 3, and 4 and various similar solutions using other glycol others or various glycols and alcohols in place of the glycol ether component were made up and tested for stability and for iodine loss on standing. Iodine loss was determined by titration for available iodine of the freshly compounded solution and of the solution after standing at room temperature in an open flask. The difference in iodine content thereby found is the loss of iodine and this is listed in the table below as loss in milligrams per gram of iodine per day.

Alcohol or glycol component: Iodine loss 1 Later precipitated I2.

Solutions as shown above wherein the iodine loss exceeded 10 milligrams per gram of iodine per day had unsatisfactory keeping qualities in that the iodine loss tended to continue at a considerable although lessened rate so that storage of such solutions beyond a very few weeks resulted in substantial loss of germicidal power. In contrast, solutions whose initial weeks loss of iodine averaged less than about 10 milligrams per day retained most of their germicidal effectiveness during long storage, ior their iodine loss decreased rapidly after the first few days and soon became insignificant. Such solutions can be stored for many months without substantial loss of iodine. Solutions prepared with 2-methoxyethanolcan be stored under ordinary conditions for one to two years and still retain or more of the original available iodine.

I claim: 7

1. An aqueous germicidal solution of one part by weight of elemental iodine, about 5 to about 15 parts by weight of a water-soluble organic anionic detergent selected from the group consisting of the alkali metal and ammonium higher alkylbenzenesul-fonates, higher alkyldiphenyl ether sulfonates and higher primary alkylsulfates and which is soluble in water at least to the extent of about 25 g. per g. of solution, and about 5 to about 15 parts of a lower alkyl monoether of ethylene glycol.

2. A solution as described in claim 1 containing 1-10 parts by weight per part of iodine of an acid which is phosphoric acid, hydrochloric acid, oxalic acid, sulfarnic acid, sodium bisulfate, or a mixture thereof.

3. A solution as described in claim 1 wherein the monoether of ethylene glycol is 2-methoxyethanol.

4. A solution as described in claim 1 wherein the monoether of ethylene glycol is Zethoxyethanol.

5. An aqueous germicidal composition consisting essentialy of one part by weight of elemental iodine, 5-15 *Duponol ME is a trademark for a commercially available grade of sodium lauryl sulfate.

5 narts of disodium dodecyld-iphenyl ether disulfonate 5-15 parts of Z-methoxyethanol, 1-10 parts of phosphoric acid, and sutficient Water to make a homogeneous solution.

References Cited by the Examiner 5 UNITED STATES PATENTS 1,429,276 9/1922 Davis 167270 2,599,140 6/1952 Taub 252 -107 2,739,922 3/ 1956 Shelanski 252-406 X 2,354,477 9/1958 Steinhauer 252-353 X 10 2,918,400 12/1959 Loonam 167-17 2,977,315 3/1961 Scheib et a1. 252- .106 3,032,505 5/ 1962 Glynn et a1. 252-107 X 6 OTHER REFERENCES Al lawala et aL, J. American Pharmaceutical Assn., Scientific Edition, Vol. 42, No. 7, July 1953, pp. 396- 401.

Terry et a1., Proceedings of the Chemical Specialties Manufacturers Assn, December 1951, pp. 69-73.

Synthetic Organic Chemicals, =pul11. of Carbide and Carbon Chem. Co., 1952, 13th Edition, pp. 32-35 and 5056.

LEON D. ROSDOL, Primary Examiner.

A. T. MEYERS, JULIUS GREENWALD,

Assistant Examiners. 

1. AN AQUEOUS GERMICIDAL SOLUTION OF ONE PART BY WEIGHT OF ELEMENTAL IODINE, ABOUT 5 TO ABOUT 15 PARTS BY WEIGHT OF A WATER-SOLUBLE ORGANIC ANIONIC DETERGENT SELECTED FROM THE GROUP CONSISTING OF THE ALKALI METAL AND AMMONIUM HIGHER ALKYLBENZENESULFONATES, HIGHER ALKYLDIPHENYL ETHER SULFONATES AND HIGHER PRIMARY ALKYLSULFATES AND WHICH IS SOLUBLE IN WATER AT LEAST TO THE EXTENT OF ABOUT 25 G. PER 100 G. OF SOLUTION, AND ABOUT 5 TO ABOUT 15 PARTS OF A LOWER ALKYL MONOETHER OF ETHYLENE GLYCOL. 